An Adaptation Technique for Multimedia Applications Based On the User Context to Manage the Service Quality

Abstract-Currently, the adaptation of multimedia applications is necessary, because documents can be accessed at anytime and anywhere with a wide variety of devices, such as PDAs, laptops and tablets. Unfortunately, in most applications dedicated to this type of problem, are essentially based on the heterogeneity of the data (image, sound, text, video and encoding format for each type), related to a user context, the context of terminal and network receiver and transmitter. In this paper. We propose an architecture on-the-fly adaptation of multimedia documents. More precisely, we propose a procedure that selects the relevant adaptation policies to build a document adapted to ensure quality of service and to consider the limits users (physical handicap, preferences of users)

Fractional order PI λD µA controller design based on Bode’s ideal function

The fractional order proportional, integral, derivative and acceleration (PI λD µA) controller is an extension of the classical PIDA controller with real rather than integer integration action order λ and differentiation action order µ. Because the orders λ and µ are real numbers, they will provide more flexibility in the feedback control design for a large range of control systems. The Bode’s ideal transfer function is largely adopted function in fractional control systems because of its iso-damping property which is an essential robustness factor. In this paper an analytical design technique of a fractional order PI λD µA controller is presented to achieve a desired closed loop system whose transfer function is the Bode’s ideal function. In this design method, the values of the six parameters of the fractional order PI λD µA controllers are calculated using only the measured step response of the process to be controlled. Some simulation examples for different third order motor models are presented to illustrate the benefits, the effectiveness and the usefulness of the proposed fractional order PI λD µA controller tuning technique. The simulation results of the closed loop system obtained by the fractional order PI λD µA controller are compared to those obtained by the classical PIDA controller with different design methods found in the literature. The simulation results also show a significant improvement in the closed loop system performances and robustness using the proposed fractional order PI λD µA controller design

On the Selection of Tuning Methodology of FOPID Controllers for the Control of Higher Order Processes

In this paper, a comparative study is done on the time and frequency domain tuning strategies for fractional order (FO) PID controllers to handle higher order processes. A new fractional order template for reduced parameter modeling of stable minimum/non-minimum phase higher order processes is introduced and its advantage in frequency domain tuning of FOPID controllers is also presented. The time domain optimal tuning of FOPID controllers have also been carried out to handle these higher order processes by performing optimization with various integral performance indices. The paper highlights on the practical control system implementation issues like flexibility of online autotuning, reduced control signal and actuator size, capability of measurement noise filtration, load disturbance suppression, robustness against parameter uncertainties etc. in light of the above tuning methodologies.Comment: 27 pages, 10 figure

Phaéton suppliant le soleil de le laisser conduire son char

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Figure allégorique à l'écoinçon

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Sébastien de Rabutin tuant un loup-cervier

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Les trois Grâces dansant devant les Dieux

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Les noces de Thétis et de Pelée

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Apollon et les Muses sur le Parnasse

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